The purpose of the Effect of Posterior Pericardiotomy on the Incidence of Atrial Fibrillation After Cardiac Surgery (PALACS, NCT02875405) trial was to determine if performing posterior left pericardiotomy at the time of cardiac surgery prevents atrial fibrillation after cardiac surgery. The purpose of the Posterior left pericardiotomy for the prevention of AtriaL fibrillation After Cardiac Surgery-Extended Follow-Up (PALACS-EF) study is to evaluate the effect of posterior left pericardiotomy on 5-year clinical outcomes.

Post-operative atrial fibrillation (POAF) is a common complication of cardiac surgery which is observed in 30-40% of patients. POAF has also been associated with stroke, systemic embolism or cardiac failure during the years after surgery. Several strategies aimed at reducing the incidence of POAF have been investigated, including beta-blockers, amiodarone, and statins, with unsatisfactory results. In the randomized prospective clinical trial, the PALACS trial, 420 patients were randomized either to the intervention group, which received left posterior pericardiotomy at time of cardiac surgery, or to the control group, which did not receive posterior left pericardiotomy at time of cardiac surgery. Posterior left pericardiotomy was associated with a reduction in the incidence of POAF after surgery, but not with improvement in 30-day patient outcomes.

This non-interventional, prospective study is an extension follow-up study (PALACS-EF) of all patients who were enrolled in the original PALACS trial. It is designed to evaluate differences in clinical outcomes between patients who received posterior left pericardiotomy (intervention) versus those who did not (control) at median follow-up of 5 years.

Inclusion Criteria:

• This study will include all the subjects enrolled in the PALACS trial

Exclusion Criteria:

• Not enrolled in the PALACS trial

Patients enrolled in the PALACS trial